Physicist Seymour Sack dies

Seymour Sack, a prominent physicist who during his 35 years at Lawrence Livermore National Laboratory (LLNL) emerged as one of the foremost U.S. nuclear weapons designers, died Tuesday, Nov. 29, in Berkeley. He was 82.

Born Sept. 8, 1929, in New York City, Sack received his Ph.D in physics from Yale in 1954, and joined the Laboratory in 1955. After nine years in the Theoretical Physics Division, Sack joined B Division in 1964.

Sack was instrumental in developing the first stages of all of the two-stage thermonuclear devices within the nuclear stockpile. His weapon design programs introduced insensitive high explosives, fire-resistant plutonium pits and other state-of-the-art nuclear safety elements. Some of his design concepts are found in every one of the U.S. stockpile weapons - whether designed by Livermore or Los Alamos.

Sack's long list of awards and recognition includes the E.O. Lawrence award in 1973, “for his innovative contributions to the theory of nuclear weapons, his development of computer codes fundamental to the design of modern nuclear weapons, his leadership in the development of new and important weapon design concepts, and his role in the engineering and testing of weapons for our nuclear stockpile.”

In 1997, he received the Fleet Ballistic Missile Achievement Award, which acknowledged his work on the W62 and W68 warheads.

In 2003, Sack was awarded the prestigious Enrico Fermi award “for his contributions to the national security of the United States in his work assuring the reliability of nuclear weapons, and thus deterring war between the superpowers.”

After his retirement from LLNL in 1990, he continued as a laboratory associate for many years and remained active in nuclear weapons design and policy issues. He continued to mentor B Division scientists well past his retirement until the year of his passing.